Docs: Add condensed cheat sheet.

Heavily inspired by:

https://gist.github.com/javierarques/0c4c817d6c77b0877fda

docs/usage/cheatsheet.md

@@ -0,0 +1,162 @@
+# UIVeri5 API cheatsheet
+
+it uses protractor beneath, so this is a good resource:
+http://angular.github.io/protractor/#/api
+
+Notes: 
+
+- Most commands return promises, so you only resolve their values through using jasmine expect API or using `.then(function(){})` syntax.
+
+- Promises are resolved by [WebdriverJS promise manager](https://github.com/angular/protractor/blob/master/docs/control-flow.md#the-webdriver-control-flow) . If you want to schedule non-api made promise into the chain, you have to use one of: 
+
+   - `.then(function(){ <your non-api code> })`
+   - [browser.wait()](http://www.protractortest.org/#/api?view=webdriver.WebDriver.prototype.wait)
+   - `browser.controlFlow().execute(<promise>)`
+
+- Node 10.15 LTS is used everywhere(jenkins), so async/await syntax can be used. However, beware, control flow may [act a bit weird when await is used:](http://www.protractortest.org/#/control-flow) 
+- Feel free to construct promises using `async` keyword though:
+```javascript
+  it('should sign in', function(){
+    ...
+    element(by.id('user_name').sendKeys("user1");
+
+    browser.controlFlow().execute(myShinyPromise)
+
+    expect(browser.getTitle()).toBe('Create Correspondence');
+
+  });
+});
+
+async function myShinyPromise(){
+  console.log('TEST IS HERE')
+  return 'something' // if you need promise resolved, not needed if using execute
+}
+```
+
+Based on this post: https://gist.github.com/javierarques/0c4c817d6c77b0877fda
+
+#### Control browser
+```javascript
+browser.testrunner.navigation.to('https://XXXXXXXX/', {auth:'plain'}); // Load address, can also use '#yourpage'
+
+browser.sleep(10000); // if your test is outrunning the browser
+
+browser.getLocationAbsUrl() // get the current address
+
+browser.ignoreSynchronization = true; // If true, uiveri5 will not attempt to synchronize with the page before performing actions - make cause wonky behaviour in further tests.
+
+```
+
+Here's a trick how to wait for something to become present/visible:
+
+```javascript
+
+browser.wait(function() {
+   return element(by.id('create')).isPresent();
+}, 5000);
+
+element(by.id('create')).click();
+```
+
+#### Check visibility 
+
+```javascript
+element(by.id('create')).isPresent() // Be careful with this: element is often present while it's not displayed...
+
+element(by.id('create')).isEnabled() //Enabled/disabled, as in ng-disabled...
+
+element(by.id('create')).isDisplayed() //Is element currently visible/displayed?
+```
+
+#### Find an element by id, model, binding, ...
+
+```javascript
+element(by.id('user_name'))
+
+element(by.css('#myItem'))
+
+element(by.control({id: "testID"}); // details: https://github.com/SAP/ui5-uiveri5/blob/master/docs/usage/locators.md#control-locators 
+
+element(by.textarea('person.extraDetails'));
+
+element(by.input('username'));
+
+element(by.input('username')).clear();
+
+element(by.buttonText('Save'));
+
+element(by.partialButtonText('Save'));
+
+element(by.linkText('Save'));
+
+element(by.partialLinkText('Save'));
+
+element(by.css('.class="cssclass"]')); 
+
+var dog = element(by.cssContainingText('.pet', 'Dog'));
+```
+
+#### Find collection of elements by css, repeater, xpath..
+
+```javascript
+var list = element.all(by.css('.items'))
+
+var list3 = element.all(by.xpath('//div'))
+
+expect(list.count()).toBe(3)
+
+expect(list.get(0).getText()).toBe('First')
+
+expect(list.get(1).getText()).toBe('Second')
+
+expect(list.first().getText()).toBe('First')
+
+expect(list.last().getText()).toBe('Last')
+```
+
+#### Send keystrokes, clear
+
+```javascript
+element(by.id('user_name').sendKeys("user1");
+
+sendKeys(protractor.Key.ENTER);
+
+sendKeys(protractor.Key.TAB);
+
+element(by.id('user_name')).clear()
+```
+
+#### Position and size, also how to deal with promises:
+
+```javascript
+element(by.id('item1')).getLocation().then(function(location) {
+  var x = location.x;
+  var y = location.y;
+});
+
+element(by.id('item1')).getSize().then(function(size) {
+  var width = size.width;
+  var height = size.height;
+});
+```
+
+#### Jasmine Matchers
+
+https://jasmine.github.io/api/edge/matchers.html
+
+```javascript
+to(N­ot)­Be( null | true | false )
+to(N­ot)­Equ­al( value )
+to(N­ot)­Mat­ch( regex | string )
+toBe­Def­ine­d()
+toBe­Und­efi­ned()
+toBe­Nul­l()
+toBe­Tru­thy()
+toBe­Fal­sy()
+to(N­ot)­Con­tain( string )
+toBe­Les­sTh­an( number )
+toBe­Gre­ate­rTh­an( number )
+toBe­NaN()
+toBe­Clo­seTo( number, precision )
+toTh­row()
+```